Induction of Mycelial Type of Development in Candida Albicans by the Antibiotic Monorden and N-acetyl-D-glucosamine

Two new effective methods for synchronous germ tube production in Candida albicans have been described. Both are based on the use of stationary grown cultures and their further incubation in an aerated simple mineral medium enriched with vitamins containing either high glucose concentration (100 mmol/1) and the antibiotic monorden being added, or N-acetyl-D-glucosamine (100 mmol/1) as the sole carbon source. On the other hand yeast morphology could be maintained in the medium with high glucose concentration. On the basis of the methods developed it was possible to compare respiration intensity, respiration quotients, and sensitivity against some metabolic inhibitors in both morphological forms. Labeling experiments showed slight differences in the time course of glycine incorporation. The mycelial cell walls contained more chitin than the yeastlike cells. Using light and electron microscopy the interrelationships between concentration of monorden, or N-acetyl-D-glucosamine, physiological state of inoculum and the germ tube frequency were determined. The results are discussed with regard to the induction of germ tubes by low glucose concentration in Candida albicans from the more general aspect of regulation of fungal morphogenesis.